Bogota, April 22 (DPA) A scandal over ties between pro-government politicians and Colombia's rightwing paramilitaries has begun to hurt relations between President Alvaro Uribe and the United States

Opposition Senator Gustavo Petro accused Uribe of leniency with paramilitaries when he was governor of the province of Antioquia in the mid-1990s.

Petro revealed a photograph of one of Uribe's brothers with former drug trade boss Fabio Ochoa, who was extradited to the US in 2001. Petro also claimed that paramilitary groups held meetings and even killed leftist rebels in estates belonging to the Uribe family.

The so-called "para-politics" scandal has already led to the arrest of eight pro-government legislators, including the brother of Foreign Minister Maria Consuelo Araujo - who resigned over the case herself - and one governor.

Uribe denied the allegations Thursday, and accused the opposition of trying to sabotage his administration's efforts to get the US Congress to approve a negotiated free trade agreement.

However, barely six weeks after US President George W. Bush visited Colombia - Washington's closest ally in Latin America - President Uribe is clearly worried.

The US Congress, controlled by Democrats, is considering freezing 55 million dollars in military aid to Colombia after a US daily reported that Colombian Army chief, General Mario Montoya, also had ties with paramilitary groups.

Former US vice president Al Gore Friday also exposed the damage done to Uribe's image. Gore refused to attend an event in Miami about the environment because he did not want to share the venue with Uribe, and later cancelled a trip to Colombia planned for August.

Gustavo Mutis, the organizer of the business fair Expogestion, told Colombia's W Radio that Gore's agency said the trip was suspended "until the truthfulness of the allegations made is confirmed or not, and this has the backing of the State Department."

Speaking in Miami, Uribe said he deplored Gore's absence.

"I hope that, when he pays attention to Colombia, he takes a good look at the Colombian citizen," Uribe said. "The people elected me on two occasions. They come to question as para-political the government which is dismantling paramilitary activity."

The United Self-Defence Groups of Colombia (AUC) initiated peace talks with Uribe's government on July 1, 2004, leading some 31,000 men to lay down their weapons.

International analyst Gustavo Puyo acknowledged the challenge that the latest scandal poses for traditionally friendly US-Colombian ties, but insisted that the country has to solve its internal problems before looking beyond its borders.

"We have to strengthen democratic institutions and justice no matter who it harms, because we Colombians cannot sacrifice ourselves and not have an opposition in order to preserve the government's good image," Puyo told DPA.

Uribe has warned that the accusations against him and his family "are starting to cause damage to the country's interests before the international community".

Senator Petro said that could not be blamed on the opposition, and that Uribe generated the phenomenon himself by "having surrounded himself with friends of the paramilitaries in his government and in Congress".